Hack Night: Conway's Game of Life

Domo had a "Mobile Hack Night" the other night.  I thought I'd slap-out a version of Conway's Game of Life.  I've always been fascinated by this simulation.

I started out with a simple implementation:

• A LifeBoard class
• you tell it the size of the game board
• you call "tick" to advance to the next step in the game
• A LifeView class
• it creates a UIView per cell in the board
• you call "changeViewBoard" to update every view to it's new state

Super simple.  And it worked -- really slowly.  So, out came instruments. And, I found the following:

• [UIView viewWithTag:tag] is *really* slow with 100s of sub-views.  I created an NSDictionary of my 100s of subviews and kablam! That issue was gone!
• I had used an NSDictionary in LifeBoard to store the state in.  I would create a key for a cell by [NSString stringWithFormat:@"%i.%i", x, y].  Another *super* slow idea.  Changed to [NSNumber numberWithInteger:(y * board.width + x)].  That was faster.
• I then moved from an NSDictionary for storing the board to the following:
• char* theBoard;
• theBoard = (char*)malloc(width*height);
• -(void)dealloc { free(theBoard); }
• Now that is FAST.

The new-and-improved version runs ata reasonable frame rate, even at large board sizes (150x150 runs several frames a second).

Please see the upgraded code on GitHub.